net/l2tpv3.c

   1 /*
   2  * QEMU System Emulator
   3  *
   4  * Copyright (c) 2003-2008 Fabrice Bellard
   5  * Copyright (c) 2012-2014 Cisco Systems
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include "qemu/osdep.h"
  27 #include <linux/ip.h>
  28 #include <netdb.h>
  29 #include "net/net.h"
  30 #include "clients.h"
  31 #include "qapi/error.h"
  32 #include "qemu/error-report.h"
  33 #include "qemu/option.h"
  34 #include "qemu/sockets.h"
  35 #include "qemu/iov.h"
  36 #include "qemu/main-loop.h"
  37 #include "qemu/memalign.h"
  38
  39 /* The buffer size needs to be investigated for optimum numbers and
  40  * optimum means of paging in on different systems. This size is
  41  * chosen to be sufficient to accommodate one packet with some headers
  42  */
  43
  44 #define BUFFER_ALIGN sysconf(_SC_PAGESIZE)
  45 #define BUFFER_SIZE 2048
  46 #define IOVSIZE 2
  47 #define MAX_L2TPV3_MSGCNT 64
  48 #define MAX_L2TPV3_IOVCNT (MAX_L2TPV3_MSGCNT * IOVSIZE)
  49
  50 /* Header set to 0x30000 signifies a data packet */
  51
  52 #define L2TPV3_DATA_PACKET 0x30000
  53
  54 /* IANA-assigned IP protocol ID for L2TPv3 */
  55
  56 #ifndef IPPROTO_L2TP
  57 #define IPPROTO_L2TP 0x73
  58 #endif
  59
  60 typedef struct NetL2TPV3State {
  61     NetClientState nc;
  62     int fd;
  63
  64     /*
  65      * these are used for xmit - that happens packet a time
  66      * and for first sign of life packet (easier to parse that once)
  67      */
  68
  69     uint8_t *header_buf;
  70     struct iovec *vec;
  71
  72     /*
  73      * these are used for receive - try to "eat" up to 32 packets at a time
  74      */
  75
  76     struct mmsghdr *msgvec;
  77
  78     /*
  79      * peer address
  80      */
  81
  82     struct sockaddr_storage *dgram_dst;
  83     uint32_t dst_size;
  84
  85     /*
  86      * L2TPv3 parameters
  87      */
  88
  89     uint64_t rx_cookie;
  90     uint64_t tx_cookie;
  91     uint32_t rx_session;
  92     uint32_t tx_session;
  93     uint32_t header_size;
  94     uint32_t counter;
  95
  96     /*
  97     * DOS avoidance in error handling
  98     */
  99
 100     bool header_mismatch;
 101
 102     /*
 103      * Ring buffer handling
 104      */
 105
 106     int queue_head;
 107     int queue_tail;
 108     int queue_depth;
 109
 110     /*
 111      * Precomputed offsets
 112      */
 113
 114     uint32_t offset;
 115     uint32_t cookie_offset;
 116     uint32_t counter_offset;
 117     uint32_t session_offset;
 118
 119     /* Poll Control */
 120
 121     bool read_poll;
 122     bool write_poll;
 123
 124     /* Flags */
 125
 126     bool ipv6;
 127     bool udp;
 128     bool has_counter;
 129     bool pin_counter;
 130     bool cookie;
 131     bool cookie_is_64;
 132
 133 } NetL2TPV3State;
 134
 135 static void net_l2tpv3_send(void *opaque);
 136 static void l2tpv3_writable(void *opaque);
 137
 138 static void l2tpv3_update_fd_handler(NetL2TPV3State *s)
 139 {
 140     qemu_set_fd_handler(s->fd,
 141                         s->read_poll ? net_l2tpv3_send : NULL,
 142                         s->write_poll ? l2tpv3_writable : NULL,
 143                         s);
 144 }
 145
 146 static void l2tpv3_read_poll(NetL2TPV3State *s, bool enable)
 147 {
 148     if (s->read_poll != enable) {
 149         s->read_poll = enable;
 150         l2tpv3_update_fd_handler(s);
 151     }
 152 }
 153
 154 static void l2tpv3_write_poll(NetL2TPV3State *s, bool enable)
 155 {
 156     if (s->write_poll != enable) {
 157         s->write_poll = enable;
 158         l2tpv3_update_fd_handler(s);
 159     }
 160 }
 161
 162 static void l2tpv3_writable(void *opaque)
 163 {
 164     NetL2TPV3State *s = opaque;
 165     l2tpv3_write_poll(s, false);
 166     qemu_flush_queued_packets(&s->nc);
 167 }
 168
 169 static void l2tpv3_send_completed(NetClientState *nc, ssize_t len)
 170 {
 171     NetL2TPV3State *s = DO_UPCAST(NetL2TPV3State, nc, nc);
 172     l2tpv3_read_poll(s, true);
 173 }
 174
 175 static void l2tpv3_poll(NetClientState *nc, bool enable)
 176 {
 177     NetL2TPV3State *s = DO_UPCAST(NetL2TPV3State, nc, nc);
 178     l2tpv3_write_poll(s, enable);
 179     l2tpv3_read_poll(s, enable);
 180 }
 181
 182 static void l2tpv3_form_header(NetL2TPV3State *s)
 183 {
 184     uint32_t *counter;
 185
 186     if (s->udp) {
 187         stl_be_p((uint32_t *) s->header_buf, L2TPV3_DATA_PACKET);
 188     }
 189     stl_be_p(
 190             (uint32_t *) (s->header_buf + s->session_offset),
 191             s->tx_session
 192         );
 193     if (s->cookie) {
 194         if (s->cookie_is_64) {
 195             stq_be_p(
 196                 (uint64_t *)(s->header_buf + s->cookie_offset),
 197                 s->tx_cookie
 198             );
 199         } else {
 200             stl_be_p(
 201                 (uint32_t *) (s->header_buf + s->cookie_offset),
 202                 s->tx_cookie
 203             );
 204         }
 205     }
 206     if (s->has_counter) {
 207         counter = (uint32_t *)(s->header_buf + s->counter_offset);
 208         if (s->pin_counter) {
 209             *counter = 0;
 210         } else {
 211             stl_be_p(counter, ++s->counter);
 212         }
 213     }
 214 }
 215
 216 static ssize_t net_l2tpv3_receive_dgram_iov(NetClientState *nc,
 217                     const struct iovec *iov,
 218                     int iovcnt)
 219 {
 220     NetL2TPV3State *s = DO_UPCAST(NetL2TPV3State, nc, nc);
 221
 222     struct msghdr message;
 223     int ret;
 224
 225     if (iovcnt > MAX_L2TPV3_IOVCNT - 1) {
 226         error_report(
 227             "iovec too long %d > %d, change l2tpv3.h",
 228             iovcnt, MAX_L2TPV3_IOVCNT
 229         );
 230         return -1;
 231     }
 232     l2tpv3_form_header(s);
 233     memcpy(s->vec + 1, iov, iovcnt * sizeof(struct iovec));
 234     s->vec->iov_base = s->header_buf;
 235     s->vec->iov_len = s->offset;
 236     message.msg_name = s->dgram_dst;
 237     message.msg_namelen = s->dst_size;
 238     message.msg_iov = s->vec;
 239     message.msg_iovlen = iovcnt + 1;
 240     message.msg_control = NULL;
 241     message.msg_controllen = 0;
 242     message.msg_flags = 0;
 243     do {
 244         ret = sendmsg(s->fd, &message, 0);
 245     } while ((ret == -1) && (errno == EINTR));
 246     if (ret > 0) {
 247         ret -= s->offset;
 248     } else if (ret == 0) {
 249         /* belt and braces - should not occur on DGRAM
 250         * we should get an error and never a 0 send
 251         */
 252         ret = iov_size(iov, iovcnt);
 253     } else {
 254         /* signal upper layer that socket buffer is full */
 255         ret = -errno;
 256         if (ret == -EAGAIN || ret == -ENOBUFS) {
 257             l2tpv3_write_poll(s, true);
 258             ret = 0;
 259         }
 260     }
 261     return ret;
 262 }
 263
 264 static ssize_t net_l2tpv3_receive_dgram(NetClientState *nc,
 265                     const uint8_t *buf,
 266                     size_t size)
 267 {
 268     NetL2TPV3State *s = DO_UPCAST(NetL2TPV3State, nc, nc);
 269
 270     struct iovec *vec;
 271     struct msghdr message;
 272     ssize_t ret = 0;
 273
 274     l2tpv3_form_header(s);
 275     vec = s->vec;
 276     vec->iov_base = s->header_buf;
 277     vec->iov_len = s->offset;
 278     vec++;
 279     vec->iov_base = (void *) buf;
 280     vec->iov_len = size;
 281     message.msg_name = s->dgram_dst;
 282     message.msg_namelen = s->dst_size;
 283     message.msg_iov = s->vec;
 284     message.msg_iovlen = 2;
 285     message.msg_control = NULL;
 286     message.msg_controllen = 0;
 287     message.msg_flags = 0;
 288     do {
 289         ret = sendmsg(s->fd, &message, 0);
 290     } while ((ret == -1) && (errno == EINTR));
 291     if (ret > 0) {
 292         ret -= s->offset;
 293     } else if (ret == 0) {
 294         /* belt and braces - should not occur on DGRAM
 295         * we should get an error and never a 0 send
 296         */
 297         ret = size;
 298     } else {
 299         ret = -errno;
 300         if (ret == -EAGAIN || ret == -ENOBUFS) {
 301             /* signal upper layer that socket buffer is full */
 302             l2tpv3_write_poll(s, true);
 303             ret = 0;
 304         }
 305     }
 306     return ret;
 307 }
 308
 309 static int l2tpv3_verify_header(NetL2TPV3State *s, uint8_t *buf)
 310 {
 311
 312     uint32_t *session;
 313     uint64_t cookie;
 314
 315     if ((!s->udp) && (!s->ipv6)) {
 316         buf += sizeof(struct iphdr) /* fix for ipv4 raw */;
 317     }
 318
 319     /* we do not do a strict check for "data" packets as per
 320     * the RFC spec because the pure IP spec does not have
 321     * that anyway.
 322     */
 323
 324     if (s->cookie) {
 325         if (s->cookie_is_64) {
 326             cookie = ldq_be_p(buf + s->cookie_offset);
 327         } else {
 328             cookie = ldl_be_p(buf + s->cookie_offset) & 0xffffffffULL;
 329         }
 330         if (cookie != s->rx_cookie) {
 331             if (!s->header_mismatch) {
 332                 error_report("unknown cookie id");
 333             }
 334             return -1;
 335         }
 336     }
 337     session = (uint32_t *) (buf + s->session_offset);
 338     if (ldl_be_p(session) != s->rx_session) {
 339         if (!s->header_mismatch) {
 340             error_report("session mismatch");
 341         }
 342         return -1;
 343     }
 344     return 0;
 345 }
 346
 347 static void net_l2tpv3_process_queue(NetL2TPV3State *s)
 348 {
 349     int size = 0;
 350     struct iovec *vec;
 351     bool bad_read;
 352     int data_size;
 353     struct mmsghdr *msgvec;
 354
 355     /* go into ring mode only if there is a "pending" tail */
 356     if (s->queue_depth > 0) {
 357         do {
 358             msgvec = s->msgvec + s->queue_tail;
 359             if (msgvec->msg_len > 0) {
 360                 data_size = msgvec->msg_len - s->header_size;
 361                 vec = msgvec->msg_hdr.msg_iov;
 362                 if ((data_size > 0) &&
 363                     (l2tpv3_verify_header(s, vec->iov_base) == 0)) {
 364                     vec++;
 365                     /* Use the legacy delivery for now, we will
 366                      * switch to using our own ring as a queueing mechanism
 367                      * at a later date
 368                      */
 369                     size = qemu_send_packet_async(
 370                             &s->nc,
 371                             vec->iov_base,
 372                             data_size,
 373                             l2tpv3_send_completed
 374                         );
 375                     if (size == 0) {
 376                         l2tpv3_read_poll(s, false);
 377                     }
 378                     bad_read = false;
 379                 } else {
 380                     bad_read = true;
 381                     if (!s->header_mismatch) {
 382                         /* report error only once */
 383                         error_report("l2tpv3 header verification failed");
 384                         s->header_mismatch = true;
 385                     }
 386                 }
 387             } else {
 388                 bad_read = true;
 389             }
 390             s->queue_tail = (s->queue_tail + 1) % MAX_L2TPV3_MSGCNT;
 391             s->queue_depth--;
 392         } while (
 393                 (s->queue_depth > 0) &&
 394                  qemu_can_send_packet(&s->nc) &&
 395                 ((size > 0) || bad_read)
 396             );
 397     }
 398 }
 399
 400 static void net_l2tpv3_send(void *opaque)
 401 {
 402     NetL2TPV3State *s = opaque;
 403     int target_count, count;
 404     struct mmsghdr *msgvec;
 405
 406     /* go into ring mode only if there is a "pending" tail */
 407
 408     if (s->queue_depth) {
 409
 410         /* The ring buffer we use has variable intake
 411          * count of how much we can read varies - adjust accordingly
 412          */
 413
 414         target_count = MAX_L2TPV3_MSGCNT - s->queue_depth;
 415
 416         /* Ensure we do not overrun the ring when we have
 417          * a lot of enqueued packets
 418          */
 419
 420         if (s->queue_head + target_count > MAX_L2TPV3_MSGCNT) {
 421             target_count = MAX_L2TPV3_MSGCNT - s->queue_head;
 422         }
 423     } else {
 424
 425         /* we do not have any pending packets - we can use
 426         * the whole message vector linearly instead of using
 427         * it as a ring
 428         */
 429
 430         s->queue_head = 0;
 431         s->queue_tail = 0;
 432         target_count = MAX_L2TPV3_MSGCNT;
 433     }
 434
 435     msgvec = s->msgvec + s->queue_head;
 436     if (target_count > 0) {
 437         do {
 438             count = recvmmsg(
 439                 s->fd,
 440                 msgvec,
 441                 target_count, MSG_DONTWAIT, NULL);
 442         } while ((count == -1) && (errno == EINTR));
 443         if (count < 0) {
 444             /* Recv error - we still need to flush packets here,
 445              * (re)set queue head to current position
 446              */
 447             count = 0;
 448         }
 449         s->queue_head = (s->queue_head + count) % MAX_L2TPV3_MSGCNT;
 450         s->queue_depth += count;
 451     }
 452     net_l2tpv3_process_queue(s);
 453 }
 454
 455 static void destroy_vector(struct mmsghdr *msgvec, int count, int iovcount)
 456 {
 457     int i, j;
 458     struct iovec *iov;
 459     struct mmsghdr *cleanup = msgvec;
 460     if (cleanup) {
 461         for (i = 0; i < count; i++) {
 462             if (cleanup->msg_hdr.msg_iov) {
 463                 iov = cleanup->msg_hdr.msg_iov;
 464                 for (j = 0; j < iovcount; j++) {
 465                     g_free(iov->iov_base);
 466                     iov++;
 467                 }
 468                 g_free(cleanup->msg_hdr.msg_iov);
 469             }
 470             cleanup++;
 471         }
 472         g_free(msgvec);
 473     }
 474 }
 475
 476 static struct mmsghdr *build_l2tpv3_vector(NetL2TPV3State *s, int count)
 477 {
 478     int i;
 479     struct iovec *iov;
 480     struct mmsghdr *msgvec, *result;
 481
 482     msgvec = g_new(struct mmsghdr, count);
 483     result = msgvec;
 484     for (i = 0; i < count ; i++) {
 485         msgvec->msg_hdr.msg_name = NULL;
 486         msgvec->msg_hdr.msg_namelen = 0;
 487         iov =  g_new(struct iovec, IOVSIZE);
 488         msgvec->msg_hdr.msg_iov = iov;
 489         iov->iov_base = g_malloc(s->header_size);
 490         iov->iov_len = s->header_size;
 491         iov++ ;
 492         iov->iov_base = qemu_memalign(BUFFER_ALIGN, BUFFER_SIZE);
 493         iov->iov_len = BUFFER_SIZE;
 494         msgvec->msg_hdr.msg_iovlen = 2;
 495         msgvec->msg_hdr.msg_control = NULL;
 496         msgvec->msg_hdr.msg_controllen = 0;
 497         msgvec->msg_hdr.msg_flags = 0;
 498         msgvec++;
 499     }
 500     return result;
 501 }
 502
 503 static void net_l2tpv3_cleanup(NetClientState *nc)
 504 {
 505     NetL2TPV3State *s = DO_UPCAST(NetL2TPV3State, nc, nc);
 506     qemu_purge_queued_packets(nc);
 507     l2tpv3_read_poll(s, false);
 508     l2tpv3_write_poll(s, false);
 509     if (s->fd >= 0) {
 510         close(s->fd);
 511     }
 512     destroy_vector(s->msgvec, MAX_L2TPV3_MSGCNT, IOVSIZE);
 513     g_free(s->vec);
 514     g_free(s->header_buf);
 515     g_free(s->dgram_dst);
 516 }
 517
 518 static NetClientInfo net_l2tpv3_info = {
 519     .type = NET_CLIENT_DRIVER_L2TPV3,
 520     .size = sizeof(NetL2TPV3State),
 521     .receive = net_l2tpv3_receive_dgram,
 522     .receive_iov = net_l2tpv3_receive_dgram_iov,
 523     .poll = l2tpv3_poll,
 524     .cleanup = net_l2tpv3_cleanup,
 525 };
 526
 527 int net_init_l2tpv3(const Netdev *netdev,
 528                     const char *name,
 529                     NetClientState *peer, Error **errp)
 530 {
 531     const NetdevL2TPv3Options *l2tpv3;
 532     NetL2TPV3State *s;
 533     NetClientState *nc;
 534     int fd = -1, gairet;
 535     struct addrinfo hints;
 536     struct addrinfo *result = NULL;
 537     char *srcport, *dstport;
 538
 539     nc = qemu_new_net_client(&net_l2tpv3_info, peer, "l2tpv3", name);
 540
 541     s = DO_UPCAST(NetL2TPV3State, nc, nc);
 542
 543     s->queue_head = 0;
 544     s->queue_tail = 0;
 545     s->header_mismatch = false;
 546
 547     assert(netdev->type == NET_CLIENT_DRIVER_L2TPV3);
 548     l2tpv3 = &netdev->u.l2tpv3;
 549
 550     if (l2tpv3->has_ipv6 && l2tpv3->ipv6) {
 551         s->ipv6 = l2tpv3->ipv6;
 552     } else {
 553         s->ipv6 = false;
 554     }
 555
 556     if ((l2tpv3->has_offset) && (l2tpv3->offset > 256)) {
 557         error_setg(errp, "offset must be less than 256 bytes");
 558         goto outerr;
 559     }
 560
 561     if (l2tpv3->has_rxcookie || l2tpv3->has_txcookie) {
 562         if (l2tpv3->has_rxcookie && l2tpv3->has_txcookie) {
 563             s->cookie = true;
 564         } else {
 565             error_setg(errp,
 566                        "require both 'rxcookie' and 'txcookie' or neither");
 567             goto outerr;
 568         }
 569     } else {
 570         s->cookie = false;
 571     }
 572
 573     if (l2tpv3->has_cookie64 || l2tpv3->cookie64) {
 574         s->cookie_is_64  = true;
 575     } else {
 576         s->cookie_is_64  = false;
 577     }
 578
 579     if (l2tpv3->has_udp && l2tpv3->udp) {
 580         s->udp = true;
 581         if (!(l2tpv3->has_srcport && l2tpv3->has_dstport)) {
 582             error_setg(errp, "need both src and dst port for udp");
 583             goto outerr;
 584         } else {
 585             srcport = l2tpv3->srcport;
 586             dstport = l2tpv3->dstport;
 587         }
 588     } else {
 589         s->udp = false;
 590         srcport = NULL;
 591         dstport = NULL;
 592     }
 593
 594
 595     s->offset = 4;
 596     s->session_offset = 0;
 597     s->cookie_offset = 4;
 598     s->counter_offset = 4;
 599
 600     s->tx_session = l2tpv3->txsession;
 601     if (l2tpv3->has_rxsession) {
 602         s->rx_session = l2tpv3->rxsession;
 603     } else {
 604         s->rx_session = s->tx_session;
 605     }
 606
 607     if (s->cookie) {
 608         s->rx_cookie = l2tpv3->rxcookie;
 609         s->tx_cookie = l2tpv3->txcookie;
 610         if (s->cookie_is_64 == true) {
 611             /* 64 bit cookie */
 612             s->offset += 8;
 613             s->counter_offset += 8;
 614         } else {
 615             /* 32 bit cookie */
 616             s->offset += 4;
 617             s->counter_offset += 4;
 618         }
 619     }
 620
 621     memset(&hints, 0, sizeof(hints));
 622
 623     if (s->ipv6) {
 624         hints.ai_family = AF_INET6;
 625     } else {
 626         hints.ai_family = AF_INET;
 627     }
 628     if (s->udp) {
 629         hints.ai_socktype = SOCK_DGRAM;
 630         hints.ai_protocol = 0;
 631         s->offset += 4;
 632         s->counter_offset += 4;
 633         s->session_offset += 4;
 634         s->cookie_offset += 4;
 635     } else {
 636         hints.ai_socktype = SOCK_RAW;
 637         hints.ai_protocol = IPPROTO_L2TP;
 638     }
 639
 640     gairet = getaddrinfo(l2tpv3->src, srcport, &hints, &result);
 641
 642     if ((gairet != 0) || (result == NULL)) {
 643         error_setg(errp, "could not resolve src, errno = %s",
 644                    gai_strerror(gairet));
 645         goto outerr;
 646     }
 647     fd = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
 648     if (fd == -1) {
 649         fd = -errno;
 650         error_setg(errp, "socket creation failed, errno = %d",
 651                    -fd);
 652         goto outerr;
 653     }
 654     if (bind(fd, (struct sockaddr *) result->ai_addr, result->ai_addrlen)) {
 655         error_setg(errp, "could not bind socket err=%i", errno);
 656         goto outerr;
 657     }
 658
 659     freeaddrinfo(result);
 660
 661     memset(&hints, 0, sizeof(hints));
 662
 663     if (s->ipv6) {
 664         hints.ai_family = AF_INET6;
 665     } else {
 666         hints.ai_family = AF_INET;
 667     }
 668     if (s->udp) {
 669         hints.ai_socktype = SOCK_DGRAM;
 670         hints.ai_protocol = 0;
 671     } else {
 672         hints.ai_socktype = SOCK_RAW;
 673         hints.ai_protocol = IPPROTO_L2TP;
 674     }
 675
 676     result = NULL;
 677     gairet = getaddrinfo(l2tpv3->dst, dstport, &hints, &result);
 678     if ((gairet != 0) || (result == NULL)) {
 679         error_setg(errp, "could not resolve dst, error = %s",
 680                    gai_strerror(gairet));
 681         goto outerr;
 682     }
 683
 684     s->dgram_dst = g_new0(struct sockaddr_storage, 1);
 685     memcpy(s->dgram_dst, result->ai_addr, result->ai_addrlen);
 686     s->dst_size = result->ai_addrlen;
 687
 688     freeaddrinfo(result);
 689
 690     if (l2tpv3->has_counter && l2tpv3->counter) {
 691         s->has_counter = true;
 692         s->offset += 4;
 693     } else {
 694         s->has_counter = false;
 695     }
 696
 697     if (l2tpv3->has_pincounter && l2tpv3->pincounter) {
 698         s->has_counter = true;  /* pin counter implies that there is counter */
 699         s->pin_counter = true;
 700     } else {
 701         s->pin_counter = false;
 702     }
 703
 704     if (l2tpv3->has_offset) {
 705         /* extra offset */
 706         s->offset += l2tpv3->offset;
 707     }
 708
 709     if ((s->ipv6) || (s->udp)) {
 710         s->header_size = s->offset;
 711     } else {
 712         s->header_size = s->offset + sizeof(struct iphdr);
 713     }
 714
 715     s->msgvec = build_l2tpv3_vector(s, MAX_L2TPV3_MSGCNT);
 716     s->vec = g_new(struct iovec, MAX_L2TPV3_IOVCNT);
 717     s->header_buf = g_malloc(s->header_size);
 718
 719     qemu_set_nonblock(fd);
 720
 721     s->fd = fd;
 722     s->counter = 0;
 723
 724     l2tpv3_read_poll(s, true);
 725
 726     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 727              "l2tpv3: connected");
 728     return 0;
 729 outerr:
 730     qemu_del_net_client(nc);
 731     if (fd >= 0) {
 732         close(fd);
 733     }
 734     if (result) {
 735         freeaddrinfo(result);
 736     }
 737     return -1;
 738 }
 739